Single use, safety blood collecting device

ABSTRACT

A shielded safety syringe comprising a cylindrical outer sleeve and an inner needle carrier holding a double-pointed needle in fluid communication with a vacuum tube and slidable within the outer sleeve between two positions. In the first position, the needle projects from the outer sleeve and is exposed for drawing blood. In the second position, the needle is retracted within the outer sleeve. The needle carrier is releasably held in the first position so that it can be readily moved into the second position after use. After the needle has been retracted into the sleeve the carrier is locked in its second position to prevent health care workers from coming into accidental contact with the used needle.

This is a continuation of application Ser. No. 141,019 filed 1/5/88, nowU.S. Pat. No. 4,892,107.

BACKGROUND OF THE INVENTION

Although hypodermic syringes may be used for blood sample collectionpurposes vacuum tube phlebotomy, where one or more samples of apatient's blood are successively drawn into respective evacuated bloodcollection tubes by way of a double ended hypodermic needle has becomethe procedure of choice.

Typically, this is currently done with a needle having two sharp ends,mounting the needle in a generally cup-shaped holder, and placing apreviously-evacuated collection tube into the holder so that theproximal end of the needle cannula pierces an elastomeric seal of thetube after the opposite needle end has been inserted into the patient'svein. As soon as the proximal needle cannula pierces the tube, thevacuum therein draws blood from the vein, through the needle, into thetube. When sufficient blood has been collected, the pre-evacuated tubeis withdrawn from the needle cannula. Often, one or more additionalevacuated tubes are inserted into the holder. After the desired numberof samples have been drawn, the needle is withdrawn from the vein anddiscarded.

After use the needle must be disposed of, typically by first removing itfrom the blood collection tube holder, recapping it, and then insertingit into a Sharp's receptacle. To prevent the reuse of the needle it issometimes broken. However, this has been found to cause aerosolcontamination frequently. Health care workers are susceptible toaccidental and potentially infectious needle strikes when they disposeof contaminated needle cannula after use. This can expose them to acommunicable disease such as AIDS or hepatitis B. To avoid infections,health care workers are now instructed neither to recap contaminatedneedles nor to "manipulate contaminated needles by hand," but rather todispose of them in Sharp's containers, molded plastic receptaclesprovided specifically for receiving waste which is potentiallybiologically hazardous, from blood precautionary patients.

Even these improved procedures do not fully protect the health careworker from accidental needle strike and the possibility of beingaccidentally exposed to a communicable disease as the act of inserting acontaminated cannula into the Sharp's container may itself result inaccidental needle strike. The worker must still handle potentiallycontaminated needles because the cup-shaped holders for receiving theneedles are typically reused, often as much as two hundred times, untilthe threads into which the needle is screwed become worn. In addition,the Sharp's containers are often not near enough to the location of use,causing the health care worker to carry the potentially contaminatedneedles to the disposal container. At other times, the health careworker may simply choose to dispose of the needle wherever and whenevermost convenient, where an exposed and contaminated needle cannula in anunexpected location may pose yet a further health hazard.

The virtually unavoidable mini-accidents caused by accidental needlestrikes have become a particularly serious concern since the spread ofthe AIDS disease, which has, in fact, been transmitted in this manner.Thus, a blood test for such diseases as AIDS and hepatitis B is nowrequired whenever such an accident occurs. The necessary testing ofhealth care workers who have received an inadvertent needle strike hasthereby led to considerable additional costs.

Recently the assignee of the present invention has developed a safetyblood collection tube holder, which is the subject of another, currentlypending patent application. Briefly, such a safety holder has aneedle/vacuum tube carrier which is slidably disposed within a tubularsleeve. The carrier is freely movable between first and second positionsin which the needle projects from the housing or is encapsulated withinthe housing so that it cannot be directly contacted by health careworkers. The carrier cannot be returned to its first position thereforethe used needle cannula is never again exposed. So long as acontaminated needle cannula is extended in an unshielded condition itposes a potential infection hazard.

SUMMARY OF THE INVENTION

The present invention provides a single use safety blood collectiondevice, which permits retraction of the hypodermic needle after its useinto the sleeve of the device, itself to thereby encapsulate the usedneedle so that the probability of sticking oneself with it is greatlyreduced, or eliminated. Once the needle is retracted after use it cannotthereafter be extended again. Thus, the present invention substantiallyreduces the probability of spreading infectious diseases as a result ofaccidental needle strikes.

This is achieved, in accordance with the present invention, by adding aself-locking mechanism to the blood collection device which was thesubject matter of the above referred to copending patent application. Tothis end, the syringe of the present invention has a needle carrierwhich is axially movable within an outer, tubular sleeve between firstand second positions in which the needle is extended or retracted,respectively. The sleeve includes two axially spaced apart, radiallyoriented openings which cooperate with an actuator integral to saidneedle carrier and that radially projects from the carrier. When theactuator is in one or the other of the two openings, the carrier is inone of the two operating positions.

In the preferred embodiment of the invention, the sleeve has an open endand a closed end including an aperture through which the needle can beextended. The distal opening is adjacent to the closed end of thesleeve, the proximal opening is adjacent to the open end thereof, and aslot extends from the first opening to the second opening and onto theopen end of the sleeve. This splits the sleeve longitudinally andpermits the opening of the slot by applying corresponding opposingforces to the slot edges.

The slot has a width where it communicates with the distal opening whichis greater than the width of the slot where it intersects the proximalopening. Moreover, the width of the slot at the distal and proximalopenings is less than the corresponding transverse dimension of theopenings and the width of the proximal opening is slightly less than thewidth of the slot at the distal opening.

The actuator is defined by a radially extending stem, an inner portionof which defines a base section attached to the needle carrier anddimensioned so that it can readily enter the distal opening. Anintermediate portion of the stem adjoining the base section is shaped sothat it fits into the proximal opening. Lastly, the actuator includes ahead attached to the intermediate stem portion and located exteriorly ofthe sleeve so that a health care worker can manually engage the headwith his or her thumb while holding the sleeve with the hand andlongitudinally slide the head and therewith the carrier from the distalto the proximal opening as is described below.

The portion of the carrier which mounts the stem is resilientlyconstructed so that it biases the stem radially outwardly. When the stemis aligned with the distal opening this biasing force moves the basesection of the stem into the distal opening and thereby securely holdsthe carrier in its first position.

To move the carrier from the distal (armed) to the proximal (safe)position, and thereby retract the needle into the sleeve, the healthcare worker presses the head radially inwardly opposing the biasingforce of the carrier to disengage the head's base section from thedistal opening and align the intermediate stem portion with the slot.Thereafter the head is retracted rearwardly, that is towards theproximal opening. Since the intermediate stem portion has a width lessthan the width of the slot at the distal opening it can readily enterthe slot. As the slot narrows towards the proximal opening the continueddistal-to-proximal movement of the head by the worker generates acomponent force which elastically deforms the sleeve and opens the slotso that the actuator can continue its movement towards the proximalopening. Once the intermediate stem portion is at the proximal opening,the resiliency of the sleeve automatically causes it to return to itsoriginal position, thereby closing the slot to its original width.Consequently, once the intermediate stem portion is in the proximalopening it confronts slot width which is less than the width of theintermediate portion. The actuator, the carrier and the needle arethereby effectively locked into their retracted position.

A particular advantage of the present invention is the fact that thealignment of the intermediate stem portion with the proximal securedopening, and the locking of the forces therein are automatic. It istherefore not necessary for the health care worker to tediouslypre-align the actuator with the proximal opening to establish the lock.The movement path for the carrier prescribed by the slot is such thatthe actuator necessarily becomes aligned with the proximal opening inthe course of retracting the used needle cannula into the housing. Oncealignment has taken place, the resilient deflection of the sleeve as thecarrier is moved towards the proximal opening is utilized toautomatically lock the intermediate stem portion in the proximal openingby permitting the housing to snap back into its relaxed position. Sincethe base section and the head of the actuator have a larger crosssection than the proximal secured opening, the actuator becomesimmovable. Since the intermediate stem portion has a width greater thanthe adjoining slot the actuator and therewith the carrier and the needleare locked in place. Thus, the present invention effectively provides aself-activating snap lock for the carrier which is engaged automaticallyby virtue of proper positioning of the actuator in the proximal opening,coupled with the fact that the movement path for the carrier prescribedby the slot is such that the actuator necessarily becomes aligned withthe proximal opening in the course of retracting the used needle cannulainto the housing.

Thus, the present invention provides a single-use, safety bloodcollection holder which is preferable to the one which forms the subjectmatter of the above-mentioned copending application because it producesa safely disposable module of one-half the volume of said copendingapplication. Moreover, the present invention is so simple that theworker handling it need not use two hands to lock the device into itssafe disposal position. The locking of the carrier in the retractedposition is a one-hand automatic operation and a necessary consequenceof the retraction of the needle into the sleeve. Consequently, thepresent invention significantly enhances the safety of used blooddrawing devices and thereby becomes an important instrument in the fightagainst the accidental or careless spread of dangerous infectiousdiseases such as AIDS or hepatitis B.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the blood collection device of the presentinvention.

FIG. 2 is an enlarged view of the portion of the locking device of FIG.1.

FIG. 3 is a cross-sectional view of the blood collection device in itsfirst position for drawing blood from a patient.

FIG. 4 is a cross-sectional view of the blood collection device in itsretracted position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-4, a syringe, or needle-vacuum tube holder 2constructed in accordance with the present invention generally comprisesan outer, tubular housing 4 having an open end 6 and a radiallyoutwardly extending flange 8 at that end. The housing defines acylindrical sleeve 10 which extends to another end of the housing thatis closed by a transverse end wall 12. A coaxial aperture 14 in the endwall permits the passage therethrough of a conventional needle 16 as isfurther described below.

A needle-vacuum tube carrier 18 is disposed within the tubular housingand axially movable between first and second positions. The carrier hasa tubular section 20 which includes an open end 22 facing in the samedirection as open end 6 of housing 4. The other end of the carrier isclosed by an end wall 24 which defines a hub 26 having a threadedportion 28 which threadably engages the needle 16 in a conventionalmanner. If desired, the needle may be otherwise. e.g., permanently fixedto the hub as by integrally molding it or thermally bonding it into thehub (not separately shown). A pre-evacuated collection tube 30 isreceived within tubular section 20 and includes an elastomeric, sealingend plug 32 which seals the interior of the tube from the exterior. Whenthe carrier is in its distal position (FIG. 3) needle 16 is extended,projects through aperture 14 through transverse end wall 12 and is readyfor use after said needle is unshielded. When the carrier is in itsproximal position (FIG. 4) the needle is disposed inside housing 4 forsafe storage after use until the syringe can be properly disposed of.

To use the blood collection tube holder, and with the carrier in itsdistal position, a laboratory technician initially attaches needle 16into the needle carrier, e.g., by threading the needle into hub 26 sothat proximal needle end 34 extends into tubular section 20 of carrier18. A protective collapsible sheathing 36 maintains the needle sterile.

Holding housing 4, the technician pierces a patient's skin with thedistal end 38 of the needle to extend it into a vein. While continuingto hold the housing with one hand the technician inserts an unusedpreviously evacuated collection tube 30 into the tubular section 20 ofthe carrier. As the tube is pushed against the protruding proximalneedle end 34, the protective sheathing 36 is first pierced by theproximal needle end which then pierces through evacuated collection tubeend plug 32.

Blood now flows from the vein through the needle into the vacuum tube.When sufficient blood has been drawn, the technician separates thevacuum tube from the carrier by axially pulling on the tube with onehand while holding the housing 4 with the other hand. End plug 32automatically reseals itself after removal of the needle cannula. Ifadditional blood samples are required the technician will repeat theabove summarized procedure to attach further, unused evacuatedcollection tubes to the carrier 18 and thereby draw additional bloodsamples.

After the last sample has been drawn the now used and contaminatedneedle is retracted by sliding the carrier relative to the housingaxially towards open housing end 6 until the distal needle end 38 isfully retracted within the tubular housing when the carrier is in itsproximal position. The housing end wall 12 and the relatively smalldiameter aperture 14 therein prevent the laboratory technician fromaccidentally contacting or striking the free end 38 of the nowcontaminated needle. The spread of infectious diseases through suchcontact is thereby prevented.

To facilitate the axial movement of carrier 18 within tubular housing 4and hold it in its two operative positions the housing includes anelongated, typically axially oriented slot 40. An actuator attached toand extending radially from carrier 18 projects through the slot to theexterior of the sleeve. The actuator includes a head or button 44 whichis readily grasped by the technician and with which the carrier can bemoved between its two operative positions as is described below.

Slot 40 extends from the open housing end 6 to a distal, round opening46 which is adjacent to housing end wall 12. The opening has a diametergreater than the width of a distal portion 48 of the slot whichcommunicates with it. A proximal opening 50 is axially spaced from thedistal opening, is proximate the open end 6 of the tubular housing, andcommunicates with a proximal portion 52 of the slot which is anextension of the distal slot portion 48. The proximal opening furthercommunicates with a remainder 54 of slot 40 as is clearly illustrated inFIG. 1.

From the foregoing it will be observed that slot 40 extends over a majorportion of the length of tubular housing 4 and segments it axially. Thehousing is constructed of a relatively flexible material, such as aninjection molded plastic, so that it can be flexibly spread apart alongthe slot to increase the width of slot 40 by applyingtangentially-opposing, outwardly directed forces to the housing on eachside of the slot. Conversely, upon the release of the forces, thehousing resiliently returns to its original as-molded position.

For reasons further described below, the proximal opening 50 is acornered opening, such as a square opening (not illustrated) or aparallelogram-shaped opening (shown in FIGS. 1 and 2) defined by fourspaced apart corners 56(a)-(c) interconnected by four, preferablystraight edges 58(a)-(c). The edge 58(a) of proximal opening 52 adjacentslot portion 52 is preferably inclined relative to the slot by an angle"A" of less than 90° and, preferably, of about 60°. All other straightedges 58(b)-(d) are correspondingly inclined to define theparallelogram-shaped hole. The transverse dimension of opening 50 equalsthe length of edge 58(a) and exceeds the width of slot 52 at the pointwhere it meets the proximal opening.

For purposes described more fully below, the width of slot portion 48where it meets distal opening 46 is slightly greater than the width ofproximal opening 52, i.e., slightly greater than the length of straightedge 58(a). Further, the diameter of distal opening 46 is greater thanthe width of the first slot portion 48.

The actuator 42 of carrier 18 is preferably integrally constructed withcarrier 18, e.g., molded therewith, and is defined by a stem 60 whichextends from tubular section 20 to actuator head 44. The stem has a basesection 62 attached to the tubular section of the carrier and a diametersubstantially equal to the diameter of distal opening 46 so that basesection can extend into the distal opening. An intermediate portion 64of the stem extends from the base 62 to head 44. It is shapedcomplementary to proximal opening 52 in sleeve 10, i.e., in theabove-described preferred embodiment of the present invention theintermediate stem portion has the shape of a parallelogram and isdimensioned so that it can be snugly received in the proximal opening ofthe sleeve.

Further, the tubular section 20 of carrier 18 is constructed of aflexible material, such as injection molded plastic, and it is shaped sothat by applying a radially inwardly directed force to actuator head 44the tubular carrier section can be resiliently deflected inwardly. In apresently preferred embodiment such a resiliently flexible mounting ofthe actuator is effected by positioning longitudinally extending cutouts66, 68 on each side of the actuator. The cutouts facilitate theabove-described inward deflection of the actuator. If desired, thetubular section 20 of the carrier can be provided with additionalopenings 68 to increase visibility of the sample as it is being drawnand to reduce its weight and thereby save material costs.

Carrier 18 is initially, usually at the factory, inserted into tubularhousing 4 by aligning stem 60 of actuator 42 with slot 40. The slot isspread apart to increase its width sufficiently (usually withappropriate fixtures) to allow the insertion of the carrier into thehousing by sliding the actuator 42 along the slot until the stem isaligned with distal opening 46. When the stem base is aligned with thedistal opening the resilient force generated by tubular section 20 ofthe carrier biases the actuator outwardly and the base section 62 intothe distal opening. This positions the carrier in its distal or "armed"position. i.e., the position at which carrier hub 26 extends through endwall aperture 14 of the housing. Since the base section 62 has a greaterdiameter than the width of the adjoining slot portion 48, the carriercannot be moved axially relative to the tubular housing even when anaxial force is applied to it.

The technician now places a fresh needle into the hub and syringe 2 isready for use by piercing a patient's skin with distal needle end 38 toreach a vein of the patient. Thereafter, one or more evacuated bloodcollection tubes are inserted into the interior of tubular carriersection 20 and the required blood samples are drawn in theabove-described manner.

After the last sample has been drawn and the last evacuated bloodcollection tube has been removed from carrier 18, the technicianwithdraws needle 16 from the patient. Immediately thereafter hecompresses actuator head 44 radially inwardly until the head engages theexterior of housing 4. This aligns intermediate stem portion 62 with theslot section 48 and since the latter is slightly wider than the former,the carrier can now be moved axially towards open housing end 6 toretract the needle into the interior of the housing. As the actuator isretracted (proximally) rearwardly, that is towards opening housing end6, the intermediate stem portion 62 engages tapered sides 70 between therelatively wide and narrow slot sections 48 and 52 over the length ofwhich the width of the slot decreases. As the actuator is movedrearwardly tangentially-opposing lateral component forces are generatedby the engagement of the intermediate stem portion 64 with the taperedslot sides. This opens the slot by flexibly spreading the housing alongthe slot to accommodate the stem portion and permit the continuedrearward movement of the carrier.

Once the intermediate stem portion 62 reaches the proximal cutout 52 theresiliency of the housing snaps it back into its original, relaxedposition. The intermediate stem portion 64 is thereby simultaneouslyaligned with and locked to the proximal opening 50 without any furthermanipulation being either necessary or possible on the part of thetechnician. Once locked, the actuator and therewith the carrier and theneedle attached thereto cannot again be moved towards the distalopening. The carrier and the needle are locked in their retractedposition because the straight edge 58(a) of the proximal openingcooperates with the corresponding side of the intermediate stem portionand prevents an axially directed force applied to the actuator head fromagain spreading the slot apart. By angularly inclining edge 58(a) asabove described, an undercut is formed. In the arrangement illustratedin FIG. 2 the undercut is at corner 56(a). It forms an anchor whichmakes it almost impossible to accidentally open the slot even whenapplying a relatively large axial force to the actuator.

Variations and modifications can be made to the present inventionwithout departing from the scope of the invention. For example, theshape of the proximal opening may be a rectangular or triangular.Further, a spring may be employed to bias the device into its secondretracted position or the button may be attached to the cylinder and theparallelogram slot to the needle carrier. It is to be understood thatthe scope of the invention is limited only by the following claims.

I claim:
 1. A blood collection device comprising:an outer sleeve and aninner needle carrier for receiving a double-pointed needle; said outersleeve including a longitudinally extending slot having first and secondlocations; said inner needle carrier being mounted within said outersleeve for axial movement between the first location, at which saidneedle is adapted to project from said outer sleeve in an exposedposition for drawing blood, and the second location, at which saidneedle is adapted to be fully disposed within said outer sleeve in aretracted position after use; said inner needle carrier including anactuator, movable radially and longitudinally relative to the outersleeve, passing through the slot; detent means, at the first location,cooperatively defined by the actuator and the slot in the outer sleeve,for releasably holding said inner needle carrier at the first locationfor use of the needle; locking means, at the second location,cooperatively defined by the actuator and the outer sleeve, fornon-releasably locking said inner needle carrier at said second locationafter the use of the needle; and the actuator and the slot configured sothe actuator is in first and second radial positions relative to thesleeve when the inner needle carrier is in the first and secondlocations.
 2. The device of claim 1 wherein the first and secondlocations are axially-aligned.